Dmitry Golubovskiy, the CEO of Esquire Russia, has posted a video of himself pronouncing the longest word in the world, on Youtube. The video is over 3 hours long! The word, which has 189,819 letters, is the chemical name for the largest known protein, titin.
In fact, comparing the longest words in each language is not as easy as you may think. It actually depends on a number of factors. If you count scientific and medical words, as shown here, place names or compound words, then the letter count obviously has the capacity to be longer.
In the Oxford English dictionary, the longest word is pneumonoultramicroscopicsilicovolcanoconiosis, which is a medical term meaning a type of lung disease. The longest non technical word is antidisestablishmentarianism.
Danish has the longest, non technical nor compounded word; at 51 letters long - Speciallægepraksisplanlægningsstabiliseringsperiode.
Agglutinative languages, such as Turkish, Tagalog, and Hungarian, can in theory have words of infinite length!
If you know of any words which are longer, let us know in the comments!